A groundbreaking study published by the Centers for Disease Control and Prevention may provide clues into what's causing the marked growth of opioid addicts, and its findings could influence the direction medical programs are headed when training current and future doctors.

The analysis shows a link between the length of an opioid prescription with the likelihood of opioid use one year after the prescription.

For patients with at least one day of opioid therapy, the rate of use one year later settled at six percent. The number increased to 13.5 percent for individuals with prescriptions lasting more than eight days. While prescriptions of more than 31 days are rare, those who received more than a month-long prescription had a 29.9 percent likelihood of using one year later.

These new findings are striking to two University of Iowa doctors who combine for nearly four decades worth of medical experience.

Hans House, a professor of emergency medicine, serves on the board of directors for the American College of Emergency Physicians.

House said the connection between prescription duration and rate of use runs counter to the training he received during his education in the mid-90s.

"Physicians were actually encouraged to prescribe more opiates and longer," said House, adding that doctors and educators believed "patients would not get addicted by appropriate pain therapy.

"That teaching, we now know, is incorrect."

House acknowledged pain is inevitable and patients are going to come to the emergency room in need of acute pain therapy, but adds this study will make future physicians more mindful of alternative approaches.

"Here at the University of Iowa, we're training our residents and students to use a full range of pain control," said House, which includes non-opioid pain medications such as ibuprofen and acetaminophen, as well as anti-depressants and anti-epilepsy medications.

While the CDC's research provides insight into opioid use, Dr. Timothy Brennan, the director of acute pain service at the university, said he'd like to know more about other factors influencing use, such as psychological background.

Like House, Brennan endorses combination therapy for pain management, describing opiates as "not optimal therapy for chronic pain" because users build up a tolerance, requiring them to increase dosage to receive the same effect.

When asked if an increased tolerance may influence overdose rates, House pointed to an opiate not prescribed as a major factor.

"The most commonly abused opiate prescription medications are starting to decrease now, but heroin has become resurgent," said House.

The decrease, in large part, is the result of increasing restrictions on opioid access, through limited formulations, shorter prescription durations, and programs to monitor patient opioid use.

"Prescriptions are harder to get, harder to get than even heroin, and heroin becomes more commonly used," said House. "The price in the street [for heroin] is actually cheaper than prescription medications."

In Iowa, heroin overdoses accounted for roughly seven percent of opioid-related deaths in 2005. In 2015, nearly one-in-four deaths from opioids was due to a heroin overdose.

Hospitals cannot prevent heroin use, and as House points out, doctors don't have much control over opioid use in general, estimating roughly two-thirds of opioid addicts get their first set of pills from friends or family members.

Ultimately, both Brennan and House agree, the CDC study could have a profound impact on the methods for education future physicians as well as determining appropriate treatment plans.